1. Field of the Invention
The present invention relates to a connecting plate which is used with being mounted onto a battery holder housing a large number of cylindrical batteries for an electric vehicle or the like.
The present application is based on Japanese Patent Application No. Hei. 9-279258, which is incorporated herein by reference.
2. Description of the Related Art
As a member for connecting plural batteries in series or in parallel, conventionally, a connecting plate 100 shown in FIGS. 25(A) and 25(B) is proposed.
The connecting plate 100 comprises a molded resin board 103 and bus bars 102 which are integrally molded with a resin. The bus bars 102 respectively connect to two batteries 101. In the molded resin board 103, a hexagonal window 103a and a rectangular window 103b through which electrode holes 102a at the ends of the batteries 101 are exposed are formed. The two batteries 101 are connected to each other by fastening the bus bars 102 respectively to nut-shaped positive and negative electrodes 101a and 101b by bolts 104. Also, a ring terminal 105 partially constituting a voltage detection circuit is connected to one of the windows or the hexagonal window 103a. A fuse case 107 is connected in series to the other end side of an electric wire 106 which is connected at one end to the ring terminal 105. The other end of the electric wire is connected to an Electronic Control Unit (ECU) which is not shown. A fuse 108 is housed in the fuse case 107. The ends of the fuse are connected to electrical contact portions 109a of female terminals 109 connected to the electric wire 106, respectively.
FIG. 26 shows another example of a conventional connecting plate.
In the connecting plate 100', plural L-shape bus bars 102'respectively having connecting legs 102b' of different lengths are moldingly fixed by a molded resin board 103. One end of each of the connecting legs 102b' protrudes from one side edge of the molded resin board 103. Ends on one side of electric wires 106 are welded to the protruding ends, respectively. The other ends of the wires are connected via a fuse case 108' to an ECU which is not shown.
In the fuse case 108', two L-shape pressure contact terminals 111 are opposingly disposed on a case substrate 110. The electric wires 106 are welded to basal plates 111a of the pressure contact terminals 111, respectively. Lead wires 108a' of fuses 108 are connected by pressure contact to slots 111c of pressure contact pieces 111b upstanding from the basal plates 111a, respectively.
The connecting plate 100 of FIG. 25 has many connecting portions in one circuit. In the voltage detection circuit, for example, there are six connecting portions indicated by letters a, b, . . . , and f. The number of parts is large. Therefore, there is a fear that the reliability of electrical connection is impaired. Furthermore, a work of fastening bolts must be conducted while holding respective ring terminals 105 one by one by a hand. As the number of electric wires to be connected is larger, therefore, the works of laying and routing the electric wires become more cumbersome and difficult.
By contrast, in the connecting plate 100' of FIG. 26, the L-shape bus bars 102' of different dimensions are used. Therefore, the plate has difficulties in cost and production management. In the same manner as the connecting plate 100, the number of parts is large and there are many connecting portions in one circuit (five portions a', b', . . . , e'). Moreover, the connecting plate has a problem in that the welding portions between the electric wires 106 and the connecting legs 102b' must be protected.
Furthermore, the electric wires 106 for the connecting plates 100 and 100' are directly connected to the batteries 101, and therefore an adequate protecting structure may be required. However, such protecting structure is complicated since bulky members such as the fuse cases 107 and 108' are attached to the electric wires 106.
FIG. 27 shows a structure in which batteries for an electric vehicle or the like are directly connected to one another without using connecting plates. In each of rectangular batteries 101', the positive and negative electrodes 101a' and 101b' are juxtaposed in one end side. Adjacent batteries are connected to each other by a main power source wire 112. An electric wire 106 (a voltage detection circuit) which has a fuse case 107 in the same manner as FIG. 25 is connected to a required electrode 101b'.
Also in this case, in the same manner as described above, the number of parts is large (the voltage detection circuit). Since the electric wires have many exposed portions, it is dangerous. Furthermore, the main power source wire 112 and the electric wire 106 of the voltage detection circuit intersect with each other, so that the wiring is complicated. This often causes the wiring to be erroneously conducted.
In order to solve these problems, it may be contemplated that, in the connecting plate 100 or 100', the connecting wire 106 is insert-molded in the molded resin board 103, and a fuse 108 or 108' serving as a circuit protecting device is interposed between the bus bar 102 or 102' and the connecting wire 106.
In order to connect the fuse 108 or the like, another terminal must be disposed between the bus bar and the connecting wire. The fuse is permanently connected to the terminals by soldering or the like. Moreover, it is preferable to, when an external force such as an impact or a pressing force is applied to the whole of the connecting plate, prevent stress from propagating to the connection portions.